It's unusual for the prosecutor’s office to release a statement about a current investigation. But the statement says because of “the filing of wrongful death lawsuits and the number of inquiries received from citizens, media, and affected families” the office decided to release the steps being taken to investigate Husel’s conduct.

Authorities have been investigating the case since Mount Carmel contacted them in early December 2018. The hospital fired Husel on December 5, and announced in January that Husel had given "excessive" doses of painkillers to dozens of patients. Since then, 22 wrongful death lawsuits have been filed against Husel and Mount Carmel by the families of Husel's patients.

According to the statement, a sergeant and four detectives from the homicide cold case unit have been investigating for Columbus Police. O’Brien and two assistant prosecutors have also been on the case.

“There are dozens of witnesses that must be interviewed, including doctors, nurses, pharmacists, and families of patients,” the statement reads. “There are thousands of pages of medical records that must first be obtained and reviewed by police and prosecutors, but then by expert medical witnesses.”

Authorities have been investigating the deaths of 29 people at Mount Carmel, although the hospital recently announced at least 35 patients were impacted by "excessive" dosing under Husel's care. The hospital also says that six patients received "excessive but not likely fatal" doses of pain medication, which accounts for the discrepancy in numbers involved in the investigation.

The prosecutor's office and Columbus Police have been working alongside Attorney General Dave Yost, the Ohio Board of Pharmacy, Ohio Board of Nursing, and the State Medical Board of Ohio, which last month suspended Husel’s license to practice medicine.

According to the statement, Husel voluntarily gave his passport to authorities while the investigation continues.

Husel will appear before the State Medical Board in July to appeal the suspension and possible permanent revocation of his license.

At least 23 other employees, including nurses and pharmacists, have been placed on administrative leave by Mount Carmel as part of an internal investigation. The hospital is currently being investigated by the Ohio Department of Health on behalf of the federal Centers for Medicare and Medicaid.

If you have information to share about the Mount Carmel investigation, please contact WOSU at paige.pfleger@wosu.org.

Dr. William Husel is accused of giving "excessive doses" of fentanyl to at least 35 patients at Mount Carmel West hospital in Columbus, as well as Mount Carmel St. Ann's. Here's a timeline of everything we know about Husel's tenure, his patients, and the lawsuits and investigations that have emerged.